ARDMS Updated SPI Exam Questions and Answers by melody

Comprehensive and Detailed Explanation From Exact Extract:

Color aliasing occurs when the Doppler shift exceeds the Nyquist limit, which is determined by the pulse repetition frequency (PRF). A low PRF reduces the Nyquist limit, making aliasing more likely.

According to sonography instrumentation reference:

“Aliasing occurs in color Doppler imaging when the Doppler shift frequency exceeds half of the PRF (Nyquist limit). A low PRF increases the likelihood of aliasing.”

Therefore, the correct answer is A: Low pulse repetition frequency.

—

Comprehensive and Detailed Explanation From Exact Extract:

A larger sample volume collects Doppler signals from a wider region, which can include multiple velocities and noise. This leads to a broader spectrum (spectral broadening) and may introduce additional noise into the signal.

According to sonography instrumentation reference:

“Increasing the sample volume size increases the likelihood of including multiple velocity components and noise, resulting in spectral broadening and reduced spectral clarity.”

Therefore, the correct answer is B: Increased noise.

—

The calipers shown in the image are used to measure the depth of structures within the ultrasound image. This performance characteristic, known as depth measurement accuracy, assesses how accurately the ultrasound system can measure the distance from the transducer to a specific point within the body. Accurate depth measurements are crucial for diagnostic purposes, ensuring that anatomical and pathological structures are correctly identified and evaluated.

American Registry for Diagnostic Medical Sonography (ARDMS) Sonography Principles and Instrumentation study materials.

Textbook of Diagnostic Sonography by Hagen-Ansert, S. L. (latest edition).

The intensity of an ultrasound beam is measured using a hydrophone. A hydrophone is a specialized device that detects and measures the acoustic pressure of the ultrasound waves in water or tissue-mimicking materials. It is highly sensitive and can measure the variations in pressure, which are used to calculate the intensity and other acoustic parameters of the ultrasound beam.

ARDMS Sonography Principles and Instrumentation guidelines

Hoskins, P. R., Thrush, A., Martin, K., & Whittingham, T. A. (2010). Diagnostic Ultrasound: Physics and Equipment.